Method and apparatus for reduction of external elastomeric connector compression force

ABSTRACT

A connector system employs a first connector moiety on an insertable miniaturized form factor card. A mobile information device (MID) has a printed circuit board having a second connector moiety and a frame mounted on the MID PCB for receiving the card. A slot is present in the frame for engagement of an elastomeric connector element in alignment with the second connector moiety. The card is positioned by the frame for alignment of the first connector moiety with the elastomeric connector element. The contact surface of the first connector moiety, as an example, multiple contact pads on the card, is extended, accomplished in the example by a matching plurality of individual metallic conductor extensions affixed to the plurality of contact pads using surface mount technology, and a cover attached to the frame is provided for urging the card into the frame and urging the extended contact surface to compress the elastomeric connector for positive contact.

RELATED APPLICATIONS

This application is a related to U.S. application Ser. No. 11/308,559filed on Apr. 6, 2006 entitled CONNECTOR FOR A HIGHLY INTEGRATED,INSTALLABLE MINIATURIZED FORM FACTOR CARD FOR WIRELESS COMMUNICATIONSFUNCTIONS having a common assignee with the present invention, thedisclosure of which is incorporated herein as though fully set forth.

BACKGROUND OF THE INVENTION—RELATED ART

U.S. patent application Ser. No. 11/308,221 filed on Mar. 13, 2006entitled MINIATURIZED FORM FACTOR WIRELESS COMMUNICATIONS CARD FORGENERIC MOBILE INFORMATION DEVICES, having a common assignee with thepresent invention and which is incorporated herein by reference in itsentirety as though fully set forth, provides a system that allowscommunications capability to be inserted into a mobile informationdevice without the usual lead times for design of wirelesscommunications directly into the device itself. This system using aminiaturized form factor card provides the ability to integratehardware, software, utilities and drivers which will allow true plug andplay functionality for end users or mobile information device designhouses. The desired functional capability is provided through aninsertable card to eliminate the requirement for a separate CPU orapplications processor in the mobile information device andadditionally, provides a complete modem solution that will supportmulti-mode and multi-band.

To enhance the space savings and weight reduction to permit more compactportable devices and flexible designs and integrate chipset and passivecomponents into a common module, the system provided in copending patentapplication Ser. No. 11/308,559 filed on Apr. 6, 2006 entitled CONNECTORFOR A HIGHLY INTEGRATED, INSTALLABLE MINIATURIZED FORM FACTOR CARD FORWIRELESS COMMUNICATIONS FUNCTIONS, having a common assignee with thepresent invention and which is incorporated herein by reference asthough fully set forth, employs integral connector systems havingstandard interfaces and indexing for mating to PC boards within themobile information device platforms and to properly index and mate theminiaturized form factor card. To further enhance the connector in sucha common module it is desirable that the connector system incorporateintegral alignment systems for accurate placement of the miniature formfactor card within the connector system and the connector system on theprinted circuit board in the generic mobile information devices.

Reliable connection of insertable cards, particularly by the end user,is a challenge for small devices with multiple pin connection. Integralelastomeric connectors provide a preferred solution, however, to provideadequate connection insertion forces may be higher than desired.

It is therefore desirable to provide a connector system which reducesthe required insertion forces while maintaining sufficient force forreliable connector contact.

SUMMARY OF THE INVENTION

The present invention provides a connector system having a firstconnector moiety on an insertable miniaturized form factor card. Amobile information device (MID) has a printed circuit board having asecond connector moiety and a frame mounted on the MID PCB for receivingthe card and having a slot for engagement of an elastomeric connectorelement in alignment with the second connector moiety, the cardpositioned by the frame for alignment of the first connector moiety withthe elastomeric connector element. The contact surface of the firstconnector moiety is extended and a cover attached to the frame isprovided for urging the card into the frame and urging the extendingmeans to compress the elastomeric connector for positive contact.

In an exemplary embodiment, the first connector moiety incorporatesmultiple contact pads on the card and the extension of the contactsurface is accomplished by a matching plurality of individual metallicconductor extensions affixed to the plurality of contact pads usingsurface mount technology. The hinged cover is movable from a first openposition to receive the card to a second closed position contacting anupper surface of the card, urging the card into the frame and theconductor extensions into compression of the elastomeric connector.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will bebetter understood by reference to the following detailed descriptionwhen considered in connection with the accompanying drawings wherein:

FIG. 1A is an isometric view of the elements of a connector system foran insertable miniaturized form factor card for employing the presentinvention;

FIG. 1B is an isometric view of the system of FIG. 1 a showing theprinted circuit board (PCB) for the card and the elastomeric connectorelements;

FIG. 2A is an isometric view of an exemplary PCB employing connectorpads for an elastomeric connector as known in the prior art;

FIG. 2B is a side section view of the card of FIG. 2 a showing a matingelastomeric connector element and a mating PCB;

FIG. 3A is an isometric view of a PCB for an insertable card employing afirst embodiment of the present invention employing connector pads withconnector extensions for an elastomeric connector;

FIG. 3B is an isometric view of the PCB of FIG. 3 a for the firstembodiment of the present invention with the connector pads having theconnector extensions installed;

FIG. 3C is a side section view of the insertable card of FIG. 3 ashowing a matins elastomeric connector element and a mating PCB in amobile device host;

FIG. 4 is an isometric view of the elements to be assembled usingsurface mount technology for the exemplary first embodiment with theassembly ascetabula;

FIG. 5A is a side view of the uncompressed elastomeric connectorelement;

FIG. 5B is a side section view showing the relative compression of theelastomeric connector by the extended pads on the PCB; and

FIG. 6 is a side sectional view of an alternative embodiment of theconector pad extensions.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A and 1B show a connector system for employing embodiments of thepresent invention having miniaturized form factor card 10 receivedwithin a frame 12 mounted to PC board 14 in a Mobile Information Device(MID) handset. Circuit connection to the MID PCB is provided by anelastomeric connector element 16, contained within connector receivingslot 18 in the frame to receive the mating elements of a first connectormoiety on the card. An exemplary elastomeric connector is a STAX™connector produced by Tyco Electronics. For the digital signalsconnector, a STAX™ model LD connector is employed in exemplaryembodiments. The elastomeric connector element engages contact pads onthe PCB in the MID for completing the circuit functionality.

The card is installed in the MID, for the embodiment of the connectorsystem shown in FIGS. 1A and 1B, by insertion vertically within frame 12which receives the external edges 20 of the card. A hinged cover 22 isprovided on the frame to secure the entire card within the frame alterinsertion, urging the connector moieties into firm engagement. PCB 24with the card covers removed is shown in FIG. 1 a with the elastomericconnector is shown exploded from the slot in the frame for greaterclarity.

As shown in FIG. 2A, connector pads 26 are incorporated cm the PCB inthe card. For prior art devices, the pads were substantially flush withthe PCB surface extending only the thickness of the etched plating layeremployed in normal processing of the PCB. The pads contact theelastomeric connector 16 as shown in FIG. 2B which provides connectionto mating connector pads 28 on the MID PCB. For fixed devices, this formof connection is satisfactory. However, for applications in which theend user may insert and remove the miniaturized form factor card,integral contact is not reliably assured with connection forces that areacceptable. Excess connection forces may score or otherwise damage thecontact pads or the elastomeric connector.

FIGS. 3A through 3C show a first embodiment of the present invention inwhich copper extension pads 30 are attached to pads 26 on the card PCB.This reduces the compression force by reducing contact areasubstantially eliminating the contact of card PCB surface on theelastomeric connector element while increasing compression distance onthe elastomeric element.

Increasing contact height of the contact pads to make them stand abovethe surface of the card PCB, or alternatively increasing contact heightof the contact pads on the MID PCB, reduces total Elastomeric connectorcontact area. With taller contact pads, the elastomeric connectorelement will only contact the pads on the card PCB rather than the cardPCB surface area which does not need to contact elastomeric connectorelement.

In the first exemplary embodiment, the pad extensions are individuallyformed from copper or other appropriate conductor material in a size tomatch pad area and provide the desired extension thickness. Theextensions are then attached to the pads using surface mount technology(SMT). As shown in FIG. 4, an acetabula 32 in a numerical control (NC)pick-and-place machine individually grasps each extension placing it ona corresponding contact pad on the card PCB which has been dotted withadhesive for temporary adherence of the extension. After placement ofthe extensions, the card PCB is processed using standard SMT solderingtechniques for permanent attachment of the extension. For initialembodiments, a thickness extension of about 0.2 to 0.3 mm is employedfor addition to the card PCB nominal thickness of 0.75 mm with aninitial elastomeric connector element height 32 of approximately 2.5 mmthereby providing a compression to a compressed height 34 ofapproximately 1.5 mm as demonstrated in FIGS. 5A and 5B. In alternativeembodiments, the pad extension is achieved using a secondary PCB 36which incorporates the individual pad extensions 38 as shown in FIG. 6thereby simplifying the extension attachment to the PCB to a singlestep. Multiple layer deposition and etching is employed in yet otheralternative embodiments for direct increase in pad height.

Having now described the invention in detail as required by the patentstatutes, those skilled in the art will recognize modifications andsubstitutions to the specific embodiments disclosed herein. Suchmodifications are within the scope and intent of the present inventionas defined in the following claims.

1. A connector system comprising: a first connector moiety on aninsertable miniaturized form factor card; a mobile information device(MID) printed circuit board having a second connector moiety; a framemounted on the MID PCB for receiving the card and having a slot forengagement of an elastomeric connector element in alignment with thesecond connector moiety, the card positioned by the frame for alignmentof the first connector moiety with the elastomeric connector element;means for extending the contact surface of the first connector moiety;and, means for urging the card into the frame and urging the extendingmeans to compress the elastomeric connector for positive contact.
 2. Theconnector system defined in claim 1 wherein the first connector moietycomprises a plurality of contact pads on the card and the extendingmeans comprises a matching plurality of individual metallic conductorextensions affixed to the plurality of contact pads.
 3. The connectorsystem defined in claim 2 wherein the conductor extensions are affixedto the contact pads using surface mount technology.
 4. The connectorsystem defined in claim 1 wherein the urging means comprises a hingedcover attached to the frame and movable from a first open position toreceive the card to a second closed position contacting an upper surfaceof the card, urging the card into the frame and the extending means forcompression of the elastomeric connector.
 5. The connector systemdefined in claim 2 wherein the elastomeric connector element has arelaxed thickness of about 2.5 mm and the conductor extensions have alength of about 0.3 mm.
 6. A method for connection of a miniaturizedform factor card on a mobile information device printed circuit boardcomprising the steps of: providing a frame on the MID PCB to receive thecard; providing a first connector moiety on the card; providing anelastomeric connector constrained by the frame and contacting a secondconnector moiety on the MID PCB; extending the first connector moietyfrom a surface of the card; urging the extended first connector moietyonto the elastomeric connector, compressing the connector at least by avertical dimension of the extension.
 7. The method of claim 6 in whichproviding the first connector moiety comprises the step of forming aplurality of contact pads on a PCB in the card and the step of extendingthe first connector moiety comprises the steps of: forming a matchingplurality of conductor extensions; and, attaching the conductorextensions to the contact pads.
 8. The method of claim 7 in which thestep of attaching comprises the steps of: positioning the extensionswith a numerically controlled machine for adhesive attachment to thecontact pads; and, soldering the extensions to the contact pads.
 9. Themethod of claim 8 wherein the step of urging the extended firstconnector moiety on the elastomeric connector comprises the steps of:providing a hinged cover attached to the frame; moving the cover from afirst open position receiving the card to a second closed positionurging the extensions into compressing contact with the elastomericconnector element.